Ion-Exchange Chromatography IEX

Elution with salt pulses A multiple step elution is performed by the introduction of, for example, 5%, 10%, 25%, 50%, and 100% of 1.5 M sodium chloride in 19 mM phosphate buffer (pH 2.5) containing 5% methanol. Each step is for 10 min and run at 0.5 mL/min. This elution method compromises analytical system dimensionality, as the peak capacity of the ion-exchange chromatography (IEX) step is equal at most to the number of salt steps. However, in the second dimension only one or two columns are needed and there is no particular limitation in the second dimension separation time as peptides are eluted in portions in a controlled manner. However, the number of salt steps is limited by the total analysis time. In this case the multidimensional system is relatively simple. 

Ion-exchange chromatography (IEX-HPLC) is intended to separate proteins based on differences in their total charge. Both anionic and cationic exchange modes are available. This technique can potentially detect and... 

Chromatography is one of the most important tools in protein purification. Chromatographic purification techniques include affinity chromatography (AC), ion exchange chromatography (IEX), hydrophobic interaction chromatography (HIC), and gel filtration (GF). These techniques separate proteins according to differences in specific protein properties. The protein property used for separation, the attributes of each technique, and its suitability for different purification steps are summarized in Table 32.7. 

Ion exchange chromatography (IEX) Charge High speed High capacity High resolution + + + + + + + + +... 

Abbreviations for type of application IEX Ion Exchange, HIC Hydrophobic interaction chromatography, AF Affinity chromatography, RP Reverse phase, IMAC Immobilized metal affinity chromatography. 

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